Power supply Control loop

Straightforward Method to Design and Simulate with SPICE the Loop Compensation Controller for All Switching Power Supplies.

Ing. Cristoforo Baldoni

In this article we ‘ll see how to find the output power stage transfer function H(s), called the Control-to-Output function,  of the most switching power supplies: BUCK, BOOST, BUCK-BOOST, HALF-BRIDGE, FULL BRIDGE, both in voltage mode control and current mode control. In spite of the complexity of the different types of power supplies that use one or more output feedback, the output power transfer function H(s), can be reduced to a few schematic categories of general validity. We’ ll see when it’s the case to consider the effects of the RHPZ, the Right Half Plane Zero, and what it means in practical terms.
Once the components for the specific power supply have been sized, we can estimate with good approximation the transfer function which describes mathematically the output power stage. As seen in the article about the determination of POLES and ZEROS by inspection,  we ‘ll identify immediately the POLES and ZEROS which characterize the different switching categories.
We ‘ll draw the Bode plots of these functions with PSpice, and, according to their characteristics, we ‘ll choose the most suitable compensator G(s), implementing the compensation network with the operational amplifiers embedded in the microcontrollers. The SPICE simulation of the open loop transfer function G(s)*H(s), will allows us to evaluate the results for the system stability. Finally, we ‘ll apply this method in two real switching power supply: a low power flyback converter and an off-line, half-bridge switching.
This method allows us to speed up the design of the compensator G(s) in the prototyping phase before the physical measurement with the instrumentation.

It’s strongly recommended the reading of these articles:

Accessing this article you can download the following SPICE simulation files about switching power supply compensation design:

-Forward function example

-Flyback function example

-Flyback function example with a Right Half Plane ZERO

-Origin POLE compensator

-Origin POLE Transfer function implementation

-Forward function compensated example

-One ZERO two POLES compensator

-One ZERO two POLES Transfer Function Implementation

-Flyback with RHPZ compensated

-Three POLES two ZEROS compensator

-Three POLES two ZEROS Transfer Function

-Transfer function of a real Flyback converter

-Compensator for the flyback converter

-Overall compensated  transfer function of the flyback converter

-Transfer function of a real Forward converter

-Compensator for the Forward converter

-Transfer function of compensator for the Forward converter

-Overall compensated  transfer function of the Forward converter

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Control System Theory and SPICE Simulation

Ing. Cristoforo Baldoni

This article provides the principles for the design and analysis of Feedback and Control Systems. The Control Systems are everywhere in the modern industrial technological world, in the laser positioning of a CD Reader,  in the very high precision positioning system of an hard disk head, and even our body has a large number of biological control systems. After introducing the basic concepts, we’ll see how easily evaluate the Open loop Transfer Function with PSPice.




1.  Processes, Open Loop and Closed Loop Control Systems (Feedback Systems)


2. Generic closed loop schematic of Feedback Systems


3. Physycal Processes Modeling, differential equations and calculations simplification with Laplace transform


4. Transfer Function, Poles and Zeros of a Transfer Function, phisical meaning


5. Natural and Forced Response, calculating Residues, when it’s possible simplify identical Zeros and Poles, dominant poles


6. Process Stability


7. Steady State Error, Type of Systems


8. Study of Transfer Function with Bode diagram. Study the Open Loop Transfer Function with SPICE.


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Altium Designer Video tutorials

Topic Video
Getting started with Altium Designer
What is a project in Altium Designer
Create a project and adding documents
How to create a schematic symbol in Altium Designer
How to wire a schematic in Altium Designer
Resolve ERC errors
How to create a PCB footprint in Altium Designer
Setting PCB footprints
keeping schematic and PCB synchronized in Altium Designer
How to place the components on the board
Routing the PCB
How to change the shape of PCB in Altium Designer
Layer stack and drill pairs


Getting Started with Altium Designer

In this article we are going to  draw a simple inverting op-amplifier with dual power supply to introduce the reader to the fundamental tools used in the Altium Designer suite.

Let’s begin creating a new schematic:

 a new blank sheet pops up


 on the top toolbar we find the icon to place part

The place part window appears

Click on the button “…” to open the Browse Libraries window

moving throughout the first list we can select a library

Once selected the library we can easily choose a library’s component


Getting Started with NI Multisim

For exploring some of the main features of this software we’  ll design an IC 20W power amplifier with a LM 1875T.

After running the program Multisim opens the default capture and simulation environment:


Now let’s select the components for our amplifier

The Component Browser dialog window appears, the components are organized into Groups and Families:

In the same Component Browser window, under the label “Components”, we can search a component editing its name, in this case LM1875T


Arduino Simulation with Proteus

We ‘ll show how to simulate the celebrated open-source electronics prototyping platform Arduino with Proteus .

 Let ‘s run ISIS Schematic:


To simulate the core of Arduino platform we need only a few components: the atmega328P Microcontroller, a Crystal and two Capacitors.Let’ s look for these devices in the library:

Click on “P” button and write atmega as keyword:


Double click on the model and this appears under Devices panel:

Same operations for the Crystal and Capacitor:



Getting Started with Proteus

Thanks for this article to archeng504


After installing Proteus , run ISIS Proteus Professional, will appear the following window interface :



Following is a brief description of each part of the function :

1. Schematic Editor window (The Editing Window): As the name implies , it is used to draw the schematic . Blue box as editable area, to put it inside the component . Note that this window is no scroll bar , you can use the preview window to change the schematic visual range .

2. Preview window (The Overview Window): It shows the two elements, one is this: When you are in the component list, select a component, it will show a preview of the element ; Another is that when you mouse focus falls on the principle diagram editor window ( ie, place the component into the schematic editor window Or after the Schematic Editor window, click the mouse ) , it will display the entire schematic diagram of the thumbnails, and will show a green box , green box which is the content of the current diagram window displays the contents of Therefore, you use the mouse to click on it to change the location of the green box , thereby changing the schematic visual range.




3. Model Selection Toolbar (Mode Selector Toolbar):

Main Modes:

1 * Select elements (components) ( selected by default )

2 * Place the connection point

3 * place a label ( the bus will be used )

4 * Place text

5 * for drawing bus

6 * for placing subcircuits

7 * for instant editing component parameters ( first click on the icon and then click the element you want to modify )


1 * terminal interface (terminals): There VCC, ground , output, input and other interfaces

2 * Device Pin : for drawing pin

3 * Emulation chart (graph): used for various analyzes, such as Noise Analysis

4 * recorder

5 * signal generator (generators)

6 * Voltage Probe: to be used when using simulation charts

7 * current probe : Using simulation to be used when using simulation charts

8 * Virtual Instrument :  in the image above, an oscilloscope

2D graphics (2D Graphics):

1 * Drawing Lines

2 * draw a variety of boxes

3 * draw various circles

4 * draw a variety of arc

5 * draw various polygons

6 * draw various text

7 * draw symbols

8 * paintings origin , etc.

4 . Component List (The Object Selector):

For the selection of components (components), terminal interface (terminals), the signal generator (Generators), simulation chart (graph) and so on. For example , when you select ” Component (Components) “, click the ” P ” button will open the selected component dialog box, select an element after ( click on the ” OK ” after ) , the device will be displayed in the list of elements , later to use this element, just in the component list can be.

5 . Toolbars direction (Orientation Toolbar):

Rotate :

The rotation angle can be an integer multiple of 90 .


Flip Horizontal and vertical flip finish . Use: Right-click the component , and then click ( left-click ) the corresponding rotation icon.

6 . Simulation Toolbar

1 * Run

2 * single-step operation

3 * Pause

4 * Stop

AVR microcontroller simulation example:

We want design an AVR driver for a LCD1602 and monitor it with an oscilloscope data lines. Parts of file formats generated by the compiler are different, such as ICC is COF, IAR is D90, GCC is COF, ELF. Proteus supports files COF, D90, HEX , etc.

Run Proteus Professional , the following window appears :



1, Add the components, in this case ATMEGA16, LM016L (LCD1602), after we’ ll add the oscilloscope.Click the “P” button to select Component dialog box appears


KEYWORDS of the dialog box , enter the ATMEGA16, get the following results :


Click OK, and close the dialog box , then the components listed in the list ATMEGA16, also find LM016L. The end result :

2 , place components: the component list, select Left ATMEGA16, in the schematic editor window, click the left button , so ATMEGA16 is placed in the Schematic Editor window . Similarly placed LM016L.


Add “ground” : Left Select model selection toolbar icon appears:

Left selection GROUND, and in the schematic editor window, left-click , so that the “ground” was placed into the Schematic Editor window .

Add Oscilloscope: Left Select model selection toolbar icon appears:

Left selection OSCILLOSCOPE, and in the schematic editor window left click , so that the oscilloscope is placed to the Schematic Editor window.

place components paying attention to place them inside the blue box of workarea.

3 . Connection. AVR, LCD ‘s VSS, VDD, VEE don’t need connections , the default VSS = 0V, VDD = 5V, VEE =-5V, GND = 0V

4 . Add a simulation file. Right click before on ATMEGA16 then select Edit Properties

in the Program File , click the File Browser dialog box, locate lcd_C.hex file, click OK to finish adding files.Set Clock Frequency at 8MHz, click OK to exit.

5 . Simulation

Click Start simulation :

Description: red for high, blue represents low, gray represents uncertainty level (floating). Running in the Debug menu, you can view the AVR related resources.

6 , the source code debugging

Proteus supports COF file debugging. Be sure to create this file in your compiler options.Complete the schematic drawing and add debug files (COF file ) , click:

the AVR Source Code window appears , if the state does not appear in the debugger , go to Debug menu to find .


Let’s say something about these icons

1 * continuous operation , it will exit the single-step debug state , and close the AVR Source Code window

2 * single-step operation , skip directly encountered Functions

3 * single-step operation , will enter its internal encountered Functions

4 * out of the current function , when using 3 * into the internal function , use it immediately on exiting the function returns a function , it should be seen in conjunction with the 3 *

5 * run to the line where the mouse

6 * Add or remove a breakpoint , the breakpoint is set using the program will stop at the breakpoint.

Getting Started with EDWinXP

In this article we ‘ll study a Series Voltage Regulator schematic circuit using the SPICE simulation software EDWinXP. After the installation, run the program

Let’s create a new project selecting Edit Page from MAINPAGE

It opens a new page


TINA Design Suite Video tutorials

Topic Video
Introductio to TINA Design Suite
Comparison of simulation and real time measurements
Real time transient recording and comparison with simulation
RC transient and AC analysys
Fourier analysis
Active band pass filter
How to make subcircuits from schematics
Test a logic gate in interactive mode
Bus example
Pic flasher circuit
VHDL circuits
Create a simple PCB
Importing PSpice Netlists into TINA